The Transverse Doppler Effect: A Possible Undergraduate Lab to Demonstrate Relativity
In the classic Pounds and Rebka General Relativity experiment of 1960, the Mössbauer effect was used to measure the gamma-ray frequency shift due to the gravitational potential energy. According to the equivalence principle, the same effect should occur in an accelerated system. An experiment to measure this effect is being assembled at Houghton College. Initial work has been done to produce a 5 ?C 57Co source by electroplating 57Co out of a cobalt solution onto steel foil, and heating the foil in a vacuum to approximately 1000 °C. The source will be placed near the edge of a thin high-speed rotating steel disc enriched in 57Fe. The 14.4 keV gamma rays from the 57Co source will penetrate the disc and be detected by a CdTe x-ray detector on the other side. Varying the radial acceleration of the rotating absorber will change the characteristic energy of the resonance absorption, resulting in a change in the gamma transmission. To reduce background, a NaI detector will detect the 122 keV gamma ray from 57Co in coincidence with the 14.4 keV gamma ray.
XXXII Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 6, 2013.
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